Pfizer Inc and Johnson & Johnson are seeking input from a U.S. Food and Drug Administration advisory committee on retaining and attracting volunteers for COVID-19 vaccine trials after a vaccine becomes available, if they know they might receive a placebo. Both U.S. companies are among a handful with pivotal, late-stage COVID-19 vaccine trials underway.
The comments in letters ahead of the meeting of expert advisers on Thursday underscore dilemmas facing leading coronavirus vaccine developers and those whose large trials are just beginning or being planned.